Japanese Patent Application Laid-Open No. 2011-193678 describes a direct power conversion device. The direct power conversion device includes a diode rectifier, an inverter and a charge/discharge circuit. The diode rectifier performs full-wave rectification on a single-phase AC voltage and outputs the voltage to a pair of DC power lines (DC link). The charge/discharge circuit is provided on the DC link, and includes a buffer circuit and a booster circuit. The buffer circuit has a switch and a capacitor that are connected in series to each other between the pair of DC power lines. The switch is located on the positive electrode side of the DC link with respect to the capacitor. The booster circuit boosts the rectified voltage from the diode rectifier to charge the capacitor. Hence the capacitor is charged with a higher voltage than the rectified voltage. Therefore, when the switch of the buffer circuit becomes conductive, this capacitor discharges electricity. The inverter receives an input of a DC voltage of the DC link, converts this to an AC voltage, and outputs the voltage.
Further, in Japanese Patent Application Laid-Open No. 2011-193678, a filter is provided on the input side of the diode rectifier. This filter is a so-called LC filter, provided with a reactor and a capacitor.
It is to be noted that as techniques related to the present disclosure, Japanese Patent No. 4135026, Japanese Patent Application Laid-Open No. 2011-050159, Japanese Patent No. 3772898, Japanese Patent No. 4766181, Japanese Patent No. 4067021, Ohnuma, Itoh, “Basic Investigation and Capacitance Reduction method of A Novel Single-Phase to Three-Phase Power Converter”, Papers of Technical Meeting on Semiconductor Power Converter, IEE Japan, SPC-08-162 (2008), Ohnuma, Itoh, “Circuit Configuration and Control Strategy of single-to-three Phase Power Converter with Active Buffer and Charge Circuit”, 2010 IEE Japan National Conference, 4-057 (2010), Ohnuma, Itoh, “Control Strategy of Single Phase to Three Phase Converter Using an Active Snubber”, 2008 IEE Japan Industry Applications Science Conference, 1-20 (2008) and Yoshiya Ohnuma, Jun-ichi Itoh, “Comparison of Boost Chopper and Active Buffer as Single to Three Phase Converter, IEEE ECCE 2011, pp. 515-521 (2011) are disclosed.